Salesforce Apex调用邮件模板

1. 正常调用无模板：

mail.setToAddresses(new List<String>{

user.Email

});

//mail.setReplyTo('[e-mail]');

//mail.setCcAddresses(null);

mail.setSenderDisplayName('EOP系统');

mail.setSubject('EOP通知（待审批）：您有未处理的【延期申请】申请,请尽快处理！');

//您当前有20条客户申请（审批类型）等待审核,请尽快处理！

//点击链接可直接打开EOP系统：http://10.110.168.105/Authority/OCBLogin

//mail.setPlainTextBody('Your Case: ' + case.Id + ' has been created.');

String body = '您当前有<b>' + delayManagerProjects.get(user.Id).size() + '</b>条延期申请等待审核,请尽快处理！<br/>';

body += '<a href=https://omrongc--eop.lightning.force.com/lightning/o/EOP_Project__c/list?filterName=00B6D000002Nq3HUAS>点击链接可直接打开EOP系统</a>';

body += '<br/><br/><br/><br/><br/><br/><br/>此邮件不可回复！';

mail.setHtmlBody(body);

System.debug('mail--->'+mail);

emailMessages.add(mail);

2. 调用模板无联系人且报错：INVALID_ID_FIELD, WhatId is not available for sending emails to UserIds.: [whatId, ************]；参考：https://salesforce.stackexchange.com/questions/1816/whatid-when-using-custom-object/144498#144498

Messaging.SingleEmailMessage email = Messaging.renderStoredEmailTemplate(emailTemplate.Id, order.OwnerId, order.Id);

String emailSubject = email.getSubject();

String emailTextBody = email.getPlainTextBody();

email.setTargetObjectId(order.OwnerId);

email.setSubject(emailSubject);

email.setPlainTextBody(emailTextBody);

email.saveAsActivity = false;

email.setToAddresses(sendAddresses);

email.setCcAddresses(ccAddresses);

emailMessages.add(email);